The observatory and adjacent refuge that he constructed for use by mountain guides and their clients attempting the Mont Blanc summit both still bear his name today, despite being rebuilt in modern times.

[1] Vallot's family were wealthy, having made their fortunes in the dye and textile business, and this allowed him to pursue and fund his many grand scientific undertakings throughout his life.

[2][3] He subsequently undertook studies at the Laboratoire de Recherche des Hautes Etudes, the Muséum National d'Histoire Naturelle and at the École Normale Supérieure in Paris.

[10] Fascinated by the mountains all around Chamonix, Vallot engaged guides not to only climb Mont Blanc, but also to undertake more difficult routes such as the Aiguille du Dru, even collecting alpine plants at the same time.

[10] In 1886 he made two ascents of Mont Blanc, but realised that daily arduous climbs with short stops at the summit were impracticable for serious scientific investigation.

After three days and nights of gruelling work, lack of appetite and terrible headaches due to the altitude - all the time taking scientific measurements - Vallot and his party returned to Chamonix where they were greeted by a deputation of flag-waving mountain guides.

[14] In his detailed published account of their undertaking and of their return to Chamonix, Vallot commented (in French) that "Astonished and confused by such a triumph, we begin to realise that by going to do scientific research at this altitude we have, without knowing it, achieved a mountaineering feat.

"[15] Recognising the impracticalities of doing scientific studies on Mont Blanc without a permanent base, Vallot subsequently engaged his cousin Henri to draw up plans to build a high-altitude observation station which he funded himself.

[17] In the summer of 1890, and with support from the Commune, Vallot employed 110 porters to carry building materials to construct his observatory on a rocky shoulder below the summit of Mont Blanc.

He and the many scientists he invited to study there made numerous observations across many disciplines, including astronomy, botany, cartography, geology, glaciology, medicine, meteorology and physiology.

[3] The first recorded case of pulmonary oedema directly attributable to the effects of high altitude (as documented by an autopsy) occurred in Vallot's observatory in 1891, with the death of a Dr. Jacottet.

The project went ahead nevertheless in 1893, but was only able to operate for a short period of time before the wooden structure began to sink into Mont Blanc's summit ice cap.

[9]: 129–130 In 1984, and as part of a plan to upgrade and return the observatory back into active use for high-altitude scientific research,[21] Vallot’s Chinese salon was dismantled and reassembled in the Alpine Museum in Chamonix.

[22][23] For some thirty years, Joseph Vallot worked alongside his cousin Henri in the latter's ambitious project to survey and create a new, detailed map of the Mont Blanc massif at a scale of 1;20000.

* [1][26][27] In 1899 he and his cousin, Henri Vallot, lent their formal support to a proposal to construct an underground railway tunnel from the town of Les Houches to just a few hundred metres below the summit of Mont Blanc.